802.1x supplicant settings in XP

Is anyone familiar with the 802.1x client in WinXP enough to know exaclty what username/password pair it is trying to pass to the server? I have been testing this out on an HP switch, with the switch itself set up as the authenticating server. I have been unsuccessful getting authentication, and have tried setting up the switch with a username/password for both accounts (administrator and myself) on my XP machine. If the supplicant is not using either of these, what is it using? The computer name? There is no password associated with that. Thanks.